I've noticed that tank pressure reads lower at 35° than at room temp. But I only care about tank pressure as a visual check that it's not empty. Last week I was changing a keg and swapped out the tank thinking it had to be running low. But I weighed it and it's still half full. As far as any other problems, I've had none.

To me it would just be another hole to drill, taking a chance on hitting a wire or line. Then you have to seal it. Choice was easy for me. It might make changing the tank easier, but its not like you do that every day.

If you're going to put a wooden collar on the keezer it makes it much easier to drill your tap holes without the worry of hitting coolant lines. You can then drill a hole to bring in your gas line from the back side. This approach gives you more floor space in the keezer that may allow another keg. The collar also provides more vertical space that may allow you to put another keg on the condenser box that most chest freezers have. That said, I almost always have an auxiliary co2 tank and regulator in my storage keezer to carb kegs and have noticed no ill effects. Good luck and post pics!

That was my method of choosing... My CO2 is on the outside, only because I can use the space on the hump. I bought my freezer specificaly because I could still fit fermenting buckets and my smaller keg there. If you can use the hump space for something useful... put the COs on the outside. Otherwise, I would put the CO2 inside and keep it simple.

I recently upgraded to a 20lb CO2 tank so I put mine outside. I have a collar on mine and can fit 6 kegs in a 7.2 cu ft chest freezer. I like to idea of not having the CO2 tank take up keg space. My kegerator is in the basement and the tank is in a spot where no one is going to accidently kick it (except me during a drunken trip to the kegerator to get just..one..more..beer... )

In case you are still looking for ideas, here's what I did with my chest freezer. I mounted a platform under the freezer with casters to make it easy to move.

Paul

I may make a platform just so it's taller, but probably won't be using casters. It won't be going anywhere. Am I seeing a 2 x 6? If so, I like it and may go that root over a 2 x 4.

The collar is around 2x6. It is actually a foam core surrounded by 1/8" hardboard. It is about 2.5 to 2.75" thick. The only thing I would change if I had to build it again is to put a solid wood core in the area where the taps are located. I have to be very careful when installing the shanks to not crush the collar.

The insulated core seems to help with condensation and efficiency (maybe).

I also installed a pipe through the collar for the CO2 line. All the lines and manifolds inside are directly connected but the external CO2 tank connection is a standard cornie quick disconnect. That allows me pull the CO2 tank without any tools to pressurize kegs and such.

Once I found those it was just finding a plumbing nipple that fit the adapter.

Paul

I used the same fittings, although it runs into a cabinet that sits next to the kegerator. I hide the CO2 tank behind a cabinet door in the cabinet next to the kegerator (between the kegerator and wine fridges):